Guide for drill collar subs



May 20, 1958 J.. J. BURRIS GUIDE FOR DRILL COLLAR SUBS 3 Sheets-Sheet 1 Filed 001;. 13, 1953 L/OJe Oh (Z Burr/J INVENTOR.

ATTORNEY May 20, 1958 J J. BURRIS. 2,335,473

I GUIDE FOR DRILL COLLAR SUBS Filed Oct. 13. 1953 3 Sheets-Sheet 2 Jose 0f) L/ Burr/s INVENTOR.

A 7'7'ORNE V .L J. BURRIS GUIDE FOR DRILL COLLAR SUBS 3 Sheets-Sheet 3 dose oh Burr/J INVENTOR I ATTORNEY May 20, 1958 Filed Oct. 15. 1953 'Illlllll "United States Patent 2,835,473 GUIDE FOR DRILL COLLAR SUBS Joseph J. Burris, Livingston, Tex. Application October 13, 1953, Serial No. 385,784 Claims. (ill. 255-28) This invention relates to a guiding and jarring sleeve for tapered drill collar subs and more particularly to a device which is adapted for application to a drill string used in the drilling of wellsand the like for the purpose of guiding the drill collar sub in the hereof the well past a key seat or other similar obstruction therein.

In the carrying out of well drilling operations and especially in the drilling of oil wells it is customary to employ a drilling bit, which is attached to the drilling string by means of a drill collar sub whose outer diameter is substantially larger than that of the string, and due to the fact that the bore of the well is usually not straight, the drill string often makes contact with the ball of the bore resulting in the formation of a groove, commonly called a key-seat which is of substantially less diameter than that of the bore. The presence of such key seats in a well bore presents a serious difficulty in the removal of the drill in that the drill string has a tendency to straighten out upon the exertion of an upward pull thereon, which frequently causes the drill collar sub to enter the key seat and become stuck therein.

Heretofore, a drill collar sub has been frequently employed whose upper end is substantially of the same external diameter as that of the drill string and which is formed with a gradual taper to an external diameter at its lower end substantially equal to that of the drill collar. A drill; collar sub of such formation has no abrupt changes in diameter and possesses the advantages of increased strength and resistance to breakage or twisting off. It has been found, however, that a drill collar sub which is so tapered has the disadvantage that it may easily enter and become wedged in a key seat thus causing the drill string to become stuck in the well bore and preventing removal of the drill therefrom. Because of this tendency to become stuck in the key seat, it has been necesary in many instances to abandon theuse of tapered drill collar subs despite the obvious advantages which they possess.

It'is an important object of the present invention to overcome the above difiiculties attending the use of tapered drill collar subs by the provision of means for guiding the drill collar sub past the key seat in the well bore and for performing a jarring operation on such guiding means in the event that the same should become wedged in a key seat.

Another object of the invention is to provide a guide for tapered drill collar subs whereby the advantages of a tapered drill collar sub may be secured without the attendant hazard of the same becoming stuck in the wellbore.

A further object of the invention is the provision of a guide for drill collar subs which permits the use of a drill collar sub having a relatively long taper, said guide embodying a sleeve adapted to fit the exterior of the sub and having an external surface positioned to operate as a guide to prevent the sticking of the equipment in a key seat or other formation presenting an obstruction in the well bore.

Another object of the invention is to provide a guide for drill collar subs of the type having a longitudinally tapering external surface and embodying a tapered sleeve which is mounted for longitudinal movement on the drill collar sub and whose internal surface'is formed with a tapered portion on a slightly different taper to that of the external surface of the sub, whereby sticking of the guide on the sub is prevented.

2,835,473 Patented May 20, 1958 A further object of the invention is the provision of a guide for tapered drill collar subs which is formed and mounted in a manner to operate as a jar to effect release of the guide and jarring sleeve in the event that the same should become stuck in the well bore'.

Another object of the invention is to provide a guide for drill collars of the type having a longitudinally tapering external surface and embodying an internally tapering sleeve mounted for longitudinal movement on the sub and having means engageable with the sub to cause the internal surface'of the guide to be spaced from the external surface of the sub whereby sticking of the guide on the sub is prevented.

A further object of the invention is the provision of a guide for drill collar subs of the type having a longitudinally tapering external surface, and embodying a sleeve mounted for longitudinal movement on the sub and having an internal tapering surface which tapers in the same direction as the external surface of the sub, and means for causing the guide to rotate with the sub when the guide is in its lowermost position on the sub.

Other important objects and advantages of-the invention will best be understood from the following detailed description, constituting a specification of the same, when considered in conjunction with the annexed drawings, wherein- Figure 1 is a vertical, cross-sectional View of a portion of a well bore showing the drill and drill string therein with a preferred form of the invention in the position on the drill collar sub which is occupied during the guiding of the drill collar and sub past a key seat or other obstruction in the bore;

Figure 2 is a cross-sectional view taken along the line 2-2 of Figure 1, looking in the direction indicated by the arrows;

Figure 3 is a view similar to that of Figure 1 illustrating/ the operation of the invention in preventing the sticking of the drill collar sub in a key seat;

Figure 4 is a fragmentary vertical, central, cross-sectional view, on an enlarged scale, illustrating a modified form of the invention and showing the same in the position which it occupies on the drill collar sub during the guiding ofthe same past an obstruction in the well bore;

Figure 5 is a cross-sectional view taken along the line 5-5 of Figure 4, looking in the direction indicated by the arrows;

Figure 6 is a fragmentary view similar to that of Figure 4, showing the position of the guide relative to the drill collar sub during the operation of the equipment in guiding the drill collar sub past a key seat;

Figures 7 and 8 are views similar to that of Figure 4 illustrating further modifications of the invention;

Figure 9 is a view similar to that of Figure 4 illustrating a further modification of the invention; and

Figure 10 is a cross-sectional view, taken along the line 1ill0 of Figure 4, looking in the direction indicated by the arrows.

Referring now to the drawings in greater detail, wherein similar parts are designated by like numerals of reference throughout the several views, the numeral 10 indi-. cates a lower section of a conventional tubular drilling string, to the lower end of which a drill collar sub 12 is attached, the sub 12 being connected at its lower end to a drill collar 14 which in turn is connected to a drill 16 of any convenient type.

At its upper end the drill collar sub 12'may be formed with a straight cylindrical portion 18, which merges at its lower end into a lower outwardly and downwardly tapering portion 20, whose lower end is of substantially the same diameter as the external diameter of the drill collar 14. The portion 13, preferably has an external diameter substantially equal to that of the drill string 3 10, and may be provided mediate its ends with an external annular enlargement 22, for a purpose later to be made apparent.

By providing a drill collar sub having a relatively long tapered portion 20, abrupt changes in the external diameter are avoided, thus providing a device which has great strength, and resistance to any tendency to twist off, which might be produced by a shoulder or other abrupt change in the external diameter of the structure at some point in its length.

In the use of well equipment provided with a drill collar sub of the type just described, it has been found that there is a tendency for the tapered portion 20 of the sub to become wedged in obstructions in the well bore, such as a key seat, indicated at K in the drawings, which is frequently formed by contact of the drill string with the wall of the bore of the well in a curved portion of the bore, and which is of substantially smaller diameter than the diameter of the bore. Under such circumstances it frequently becomes very difiicult or impossible to withdraw the drilling bit from the well bore, thus greatly delaying the progress of the drilling operation and involving expensive fishing or other well-clearing operations to again place the well in condition for further drilling.

In order to guide the drill collar sub and drill collar past such a key seat, guide means is provided in accordance with the invention, which in the present illustration takes the form of a tapered sleeve element 24, which surrounds the drill collar sub 20, and is mounted for limited longitudinal movement thereon.- In the form of the invention illustrated in Figures 1, 2 and 3 of the drawings, the guide element 24, has an internally tapered portion indicated at 26, which may have substantially the same taper as that of the lower portion 20, of the drill collar sub, or may vary slightly therefrom, and at its upper end the guide and sleeve element is preferably provided with a portion indicated at 28 of cylindrical shape, corresponding to the shape of the upper end portion 18, of the sub. 3

At its lower end, which is the location at which the guide element is of largest external diameter, the element may be provided with an externally beveled end portion 30, whose external diameter preferably does not exceed the external diameter of the drill collar 14.

The guide element is substantially shorter than the distance between the external annular enlargement 22 of the drill collar sub and the lower end portion 21, of the same, whereby the guide element may move freely up and down on the sub, such movement being limited by the engagement of the upper end of the guide with the enlargement 22, or by engagement with the drill collar sub upon downward movement of the guide relative to the sub.

In the operation of the equipment, constructed and arranged as described above, the drill 15, is lowered into the well attached to the drilling string and rotated therein, the guide element 24 being in the position indicated in Figure 1 during the normal progress of the drilling operation. When it is desired to remove the bit from the well bore the drilling string is moved upwardly, and in the event that a key seat such as that indicated at K is present in the well bore above the drill collar 14, the guide element will serve to guide the drill collar sub past the key seat in the bore in the same manner as would be accomplished by the tapering portion 20 of the drill collar sub if the sleeve 24 were not present. During such withdrawal of the drilling string the external tapered surface of the sleeve. engages the internal surface of the well bore on each side of the key scat K, as best seen in Figure 2 of the drawings to prevent the sleeve from entering the key seat and to guide the drill collar past the seat. Should the guide element become wedged in the bore, due to the curvature of the bore in the vicinity of a key seat during such upward movement of the drill string, so that the bit cannot be withdrawn from the bore, then the drill string may be moved downwardly to engage the external enlargement 22, with the upper end of the guide to perform a jarring action on the guide to disiodge the guide by downward movement in the bore. In the event that the guide becomes so tightly wedged in the bore that it can not be readily moved downwardly therein by the weight of the drill string, the string may be moved up and down to secure a jarring action of the enlargement 22 on the upper end of the guide to jar the same loose, and by repeated manipulation of the drill string the drill collar may in this manner, be moved past the key seat to permit the withdrawal of the bit from the bore.

In the form of the invention illustrated in Figures 4, 5 and 6 of the drawing, a drill collar sub 112, of similar design to the sub 12 of the previously described form of invention may be employed, which is provided with a similar upper end portion 115, and which has thereon an external enlargement 122, and is formed with a downwardly and outwardly tapering external surface portion 120. In this form of the invention the sub may be formed with an external annular upwardly facing shoulder 134, which may be rounded off in the location where it merges with the external tapering surface of the sub above and below the shoulder, so that no sharply defined corners are formed thereby.

A sleeve-like guide and jarring element 124, of generally similar configuration to that of the sleeve 24, previously described, surrounds the sub 112, and is movable longitudinally thereon. This guide element is preferably formed with a tapering portion 126, and an upper end cylindrical portion 128, of such size that the interior surface of the guide is slightly larger than the external surface of the sub within the guide when the guide is in its lowermost position on the sub. At its lower end the guide may be formed as indicated at 136, to seat on the external annular shoulder 134 of the sub. By this construction the guide is loosely mounted on the sub and is prevented from becoming wedged thereon by engagement of the internal surface of the guide with the external surface of the sub, so that the guide may always move freely longitudinally of the sub between the external annular shoulder 134 and the external enlargement 122. As in the previously described form of the invention, the lower end of the guide preferably does not exceed in external diameter, the external diameter of the drill collar below. The guide 124 may, if desired, be provided with one or more external lugs 138, and with internal teeth within the upper end portion 128, which intermesh with external teeth 158 formed on the sub 112 when the guide is in its lowermost position on the sub.

In the operation of the form of the invention illustrated in Figures 4, 5 and 6 the equipment is lowered into the well bore in the condition illustrated in Figure 4, wherein the guide is in its lowermost position seated on the external shoulder 134 of the sub. Upon upward movement of the drill stem in the well bore, should there be a key seat in the bore, the guide 124 serves to guide the sub and drill collar past the seat, and in the event that the guide should become wedged in the bore, the drill string may be lowered to engage the external enlargement 122 with the upper end of the guide to free the guide. The lugs 138 of the guide extend laterally beyond the external surface of the guide in position to engage the surrounding wall of the well bore to aid in preventing the guide from entering the key seat and upon rotation of the drill string'while withdrawing the same from the bore, the guide will be rotated to cause the lugs 138 to engage the wall of the bore to hold the guide centered in the bore away from the key seat thus preventing the guide from becoming wedged in the key seat.

A further modification of the invention is illustrated in Figure 7 wherein the drill collar sub, shown at 212, and

the guide element 224 are of similar design to those pre- I viously described. In this form of the invention, however, the lower end of the guide is provided with a beveled end surface 242, and the drill collar sub has an external enlargement providing an upwardly facing tapered shoulder 240, upon which the beveled end face 242 may be seated when the guide is in its lowermost position. The guide element 224 is preferably somewhat larger internally than tapered portion 220 of the drill collar sub, as is indicated at 226, so that when the guide is seated on the shoulder 240 the guide does not closely fit the exterior surface of the sub, whereby the guide is prevented from sticking on the sub.

In Figure 8 of the drawings there is illustrated a further modification of the invention, wherein the drill collar sub may be formed with a plurality of externally tapering upwardly facing shoulders 344 and 346, and the lower end of the guide element 324 is formed with corresponding beveled lower end surfaces 348 and 350, which seat on the shoulders 344 and 346 when the guide is in its lowermost position. The guide 324 is also preferably of somewhat larger internal dimension than the corresponding external dimension of the drill collar sub whereby the guide is prevented from binding or wedging on the sub in the operation of the equipment. The guide may be provided with one or more openings 354, leading from the interior to the exterior thereof, whereby any foreign material which may enter between the sub and the guide during the operation of the apparatus may readily escape. In other respects this form of the invention is similar in construction and operation to those previously described.

Figure 9, illustrates a somewhat different form of the invention, wherein the drill collar sub 412 is of similar design to those previously described in connection with the forms of the invention shown in Figures 1, 4, 7 and 8. In this form of the device, however, the guide 424 may have an external surface which'is substantially cylindrical and may have an external diameter somewhat larger than that of the drill collar, whereby the drill collar sub and drill collar may be guided past a key seat in" the well bore, and a jarring action may be obtained, if desired, by engagement of the external enlargement 422 of the sub with the upper end face 462 of the guide. In other respects this form of the invention is constructed and operated in substantially the same manner as the form illustrated in Figures 1 and 2.

While the invention has been disclosed herein in connection with specific embodiments of the same, it will be understood that this is intended by way of illustration only, and that numerous changes can be made in the construction and arrangement of the various parts without departing from the spirit of the invention for the scope of the appended claims.

Having thus clearly shown and described the invention what is claimed as new and desired to secure by letters patent is:

1. Well drilling equipment comprising a tubular drill string, a drill collar sub connected to said string and a drill collar having an external diameter greater than that of said string connected to said sub, said sub having an external diameter at its upper end which is substantially the same as the external diameter of said string and smaller than the external diameter of said collar and being formed with a downwardly and outwardly tapering external surface, a tubular sleeve surrounding and movable longitudinally on said sub and having an internal tapering surface corresponding to and positioned for engagement with the tapering surface of said sub upon relative longitudinal movement of the sleeve and sub in one direction and for disengagement from the tapering surface of said sub upon relative lmgitudinal movement of the sleeve and sub in the other direction and an external inwardly and upwardly tapering surface position for engagement with the surrounding wall of a well bore at a location above the lower end of said sub and means on said sub positioned for engagement with the upper end of said sleeve upon downward movement of the sub in the sleeve to deliver an impact on said sleeve.

2. Well drilling equipment comprising a tubular drill string, a drill collar sub connected to said string and a drill collar connected to said sub, said sub having a portion adjacent its lower end which is of substantially the same external diameter as the external diameter of said collar and having an upwardly and inwardly tapering external surface, a tubular sleeve surrounding and movable longitudinally on the sub and having an internal tapering surface corresponding to and positioned for engagement with the tapering surface of said sub upon relative longi tudinal movement of the sleeve and sub in one direction and for disengagementfrom the tapering surface of said sub upon relative longitudinal movement of the sleeve and sub in the other direction and an external inwardly and upwardly tapering surface positioned for engagement with the surrounding wall of a well bore at a location above the lower end of said sub and means on said sub positioned for engagement with the upper end of said sleeve upon downward movement of the sub in the sleeve to deliver an impact on said sleeve.

3. Well drilling equipment comprising a tubular drill string, a drill collar sub connected to the string and a drill collar connected to the sub, said sub having an upwardly and inwardly tapering external surface, a tubularsleeve surrounding and longitudinally movable on the sub and having an internal tapering surface corresponding to the tapering surface of the sub and an external upwardly and inwardly tapering surface positioned for engagement with the surrounding wall of a well bore at a location above the lower end of said sub, said sleeve being shaped for engagement with the sub to hold said internal surface out of contact with said external surface of said sub when said sleeve is in its lowermost position on the sub and means'on said sub positioned to engage the upper end of said sleeve upon downward movement of the sub in the sleeve.

4. Well drilling equipment comprising a tubular drilling string, a drill collar sub connected to the string and a drill collar connected to said sub, said sub having an upwardly and inwardly tapering external surface, a tubular sleeve surrounding and longitudinally movable on said sub and having an internal surface corresponding to said external surface of the sub, and interengageable means on the sleeve and sub positioned to be disengaged upon relative longitudinal movement of the sleeve and sub in one direction to permit relative rotation of the sleeve and sub and to be interengaged upon relative longitudinal movement of the sleeve and sub in the other direction to cause the sleeve to rotate with the sub.

5. Well drilling equipment comprising a tubular drilling string, a drill collar sub connected to the string and a drill collar connected to said sub, said sub having an upwardly I and inwardly tapering external surface, a tubular sleeve References Cited in the file of this patent UNITED STATES PATENTS 2,212,067 Hoflfoss Aug. 20, 1940 2,620,164 Burris Dec. 2, 1952 FOREIGN PATENTS 622,749 Germany Dec. 5, 1935 

